I am starting an aqua farm to raise tilapia and filter my fish tanks through media grow beds I am plannining to build my grow bed and fish tanks out of wood need the cheapest and best way to waterproof both my grow beds are going to be 8' x4' x1' my fish tank is going to be between 8' and 12' long 4' wide and 3' deep right now I got a 55 gal glass aquarium for my breeder fish and going to filter it in a 2' wide 4' long and 1' deep plywood grow bed it will be filled with 3/4" pea gravel media to grow my plants the water from the aquarium will pump up into it and drain out the bottom back into the aquarium I was thinking of using putting polyuerthane on the wood then silicon on the joints and then spraying this black truck bed coating on the whole thing does anyone know anything about using truck bed coating to waterproof and if it is fish and plant safe also UV resistant
look forward to any comments and suggestions